How to load Jinja2 template with values after form submission

Question

I have a form in a Jinja2 template. This is what I'm trying to do with it:

• After a user submits the form, a handler in the backend enqueues an asynchronous task.
• The handler then reloads the current page with the form filled with the user provided values.

What is the best way to do this ? For example say I have a <select> input in my form that looks like this:

  <select id="shift_selected" name="shift_selected">
  {% for shift in Shifts %}
    <option value="{{ shift }}" {{ 'selected' if shift == selected_shift }}>{{ shift }}</option>
  {% endfor %}
  </select>

Now to re render the page after the form has been submitted,

• my handler has to parse the input, get the value of 'shift_selected'

• Then set the value of 'selected_shift'.

args['selected_shift'] = self.request.get("selectedShift")

template.render(args)

The handler essentially receives some data in form values and sends the same data back as a template variable value. Is there a better way to do this. If done for a long form this method is quite tedious.

Answer 1

Actually, you can even pass request object as a param to Jinja template. Or write a function to copy all the GET or POST parameters in request to Jinja template parameters.

args['request'] = self.request
template.render(args)

<select id="shift_selected" name="shift_selected">
{% for shift in request.get('selectedShift') %}
    <option value="{{ shift }}" {{ 'selected' if shift == selected_shift }}>{{ shift }}</option>
{% endfor %}
</select>